leetcode 92. Reverse Linked List II

布满荆棘的人生 2022-07-29 09:20 22阅读 0赞

Reverse a linked list from position m to n. Do it in-place and in one-pass.

For example:
Given 1->2->3->4->5->NULL, m = 2 and n = 4,

return 1->4->3->2->5->NULL.

Note:
Given m, n satisfy the following condition:
1 ≤ m ≤ n ≤ length of list.

  1. class Solution {
  2.  public:
  3.      ListNode* reverseBetween(ListNode* head, int m, int n) {
  4.          if (n - m < 1)
  5.              return head;
  6.          ListNode*p = head,*pre=NULL;
  7.          int k = 1;
  8.          while (k < m)
  9.          {
  10.              pre = p;
  11.              p = p->next; k++;
  12.          }
  13.          ListNode*hea = p,*p1=p->next;
  14.          while (k < n)
  15.          {
  16.              ListNode*nxt = p1->next;
  17.              p1->next = hea;
  18.              hea = p1;
  19.              p1 = nxt;
  20.              k++;
  21.          }
  22.          if (pre == NULL)
  23.              head = hea;
  24.          else
  25.              pre->next = hea;
  26.          p->next = p1;
  27.          return head;
  28.      }
  29.  };

accepted

发表评论

表情：
评论列表 （有 0 条评论，22人围观）

还没有评论，来说两句吧...

相关阅读